Recently, lithium-ion secondary batteries have been used in a wide range of areas, such as cellular phones and notebook-size personal computers, because they have large capacities. Moreover, in recent years, lithium-ion secondary batteries have been also investigated to use as a driving source for vehicle. A positive electrode of a lithium-ion secondary battery comprises ceramics, such as lithium composite oxides, and lithium ions come in and out between ceramic layers at the time of charging and discharging. A negative electrode comprises carbon, and the lithium ions come in and out between carbon layers at the time of charging and discharging. Thus, sorbing and desorbing (or occluding and releasing) of the lithium ions are repeated at the positive electrode and negative electrode, and thereby electric energy is produced.
Lately, as disclosed in WO2010/073978 (i.e., Patent Application Publication No. 1), a lithium battery which uses lithium metal for a negative electrode and metallic copper for a positive electrode has been developed. In this lithium battery, lithium metal is plated onto the surface of the negative electrode while copper is dissolved at the positive electrode at the time of charging; whereas the metallic copper is plated onto the surface of the positive electrode while lithium is dissolved at the negative electrode at the time of discharging. Such battery reactions resulting from precipitation and dissolution of plating are simple compared with the battery reactions of common lithium-ion secondary battery. Hence, upgrading the output of battery can be expected. Moreover, since the electrodes are metals, the conductivities of the electrodes themselves are good. Consequently, the metals are available for electrodes as they are without using any current collector.